International affairs: $13.22 billion, up 12.9 percent after inflation

Environment and animals: $6.96 billion, up 7.7 percent after inflation

In most years, some two-thirds of Americans donate to charity.

The second-leading source of donations were foundation grants at $38.5 billion. Other sources were $23 billion from bequests and $15.7 billion from corporations, which was down by an inflation-adjusted 1 percent from 2006.